Yellow azo dye and process of making same.



UNITED STATES PATENT OFFICE.

FRIEDRICH RUNKEL, OF ELBERFELD, GERMANY, ASSIGNOR TO FARBEN- FABRIKEN OFELBERFELD (10., OF NEW YORK, N. Y., A CORPORATION OF NEV YORK.

YELLOW AZO DYE AND PROCESS OF MAKING SAME.

fiPEGIFIGl-LTION forming part of Letters Patent No. 719,049, datedJanuary 27, 1903.

Application filed October 11, 1902. Serial No. 126,942. (No Specimens.)

T aZZ whom it ntay concern:

Beit known that LFRIEDRICH RUNKEL,doctor of philosophy, chemist,(assignor to the FARBENFABRIKEN or ELBERFELD Go. ,of New York,) residingat Elberfeld, Germany, have invented a new and useful Improvement inYellow Azo Coloring-Matter and Process of Making Same; and I herebydeclare the following to be a clear and exact description of myinvention.

My invention relates to the production of new valuable azo dyestuffs bycombining the hitherto-unknown sulfonic acids of the indol group witharomatic diazo compounds, such as diazobenzene, diazonaphthalene,diazoazobenzene, or the like. The said new sulfonic acids of the indolseries containing the sulfonic groups in the benzene nucleus can beobtained by treating with sulfonating agents indol derivatives, such asalpha-methylindol, (Pr -methylindol,) B -Pr -dimethylindol, orderivatives thereof substituted in the benzene nucleus or alkylated inthe imido group or the like.

The starting materials for the preparation of the new indol sulfonicacids can be prepared according to the method of E. Fischer (see AnnalencZer Chemz'e, Vol. 236, pages 153 to 155) by melting together thecorresponding ketohydrazones and zinc chlorid.

The new dyestuifs produced with the aid of the above-mentioned indolderivatives are from yellow to brown powders soluble in water and inammonia and dyeing wool from yel- 3 5 low to orange shades.

In carrying out my new process practically I can proceed as follows, theparts being by weight: 13.1 parts of alpha-methylim dol (Pr methylindol)of the formula V li-cn,

are stirred into twenty-six parts of sulfuric monohydrate under cooling.Into the res ulting mixture one hundred and five parts of fumingsulfuric acid (twenty per cent. of S0 are slowly run, taking care thatthe temperago ture does not rise higher than about 60 centigrade. Thereaction is finished when a testportion is entirely soluble in water orwhen a test portion treated with an excess of alkali and shaken withother does not give up any more alpha-methylindol to the ether. Whenthis point is reached, the reaction mass is poured into one thousandparts of ice-water. To this solution a diazo solution prepared in theusual manner from 10.7 parts of orthotoluidin is added. The liquidassumes a yellow color, and after some hours the dye stuff sulfonic acidis separated in the shape of orange-red flakes. The separation iscompleted by the addition of a common salt. It is filtered 0E, Washedwith a solution of common salt, and dissolved in a hot solution of eightparts of sodium carbonate in five hundred parts of Water. The newcoloring matter is then separated from this solution by the addition ofcommon salt. It represents a yellow powder, being soluble in water,alcohol, and ammonia with a yellow color. It is dissolved byconcentrated sulfuric acid of 66 Baum, with an orange-yellow color, anddyes wool yellow shades very fast to light. The process proceeds in ananalogous manner-if other indol sulfonic acids or if other diazocompounds, diazoazo compounds, or tetrazo compounds are used.

I-Iereunder I give the shades of some of the new dyestufis:

Dyestufi prepared D I f by combination Withthesulfonicacidofyew00 tom ofdiazotizedacld'bat 5 Anilin a-methylindol Yellow. O-toluidin B -meth lPr -ethyl-2- Yellow.

methy indol.

M-toluidin wmethylindol Yellow. Pxylidin Pr -2-dimethylindol Yellow. cOchloroamlm Pr -ethyl-2-methylindol Yellow. 9 O-nitranilin Ir-2-dimethylindol Orange-yellow. P-nitranilin a-meth lindo1 Orange.u-naphtln lamin... Pr -2- imethylindo Orange. fi naphthylaminn.wmethylindol Yellow.

Having now described my invention and in 5 what manner the same is to beperformed, what I claim as new, and desire to secure by Letters Patent,is

1. The process for producing new azo dyestuffs by first combining diazoderivatives of aromatic amins with the sulfonic acids of indolderivatives and secondly isolating the dyestuffs thus obtained,substantially as hereinbefore described.

2. The process for producing a new azo dyestufi by first combiningdiazotized orthotolnidin with the sulfonic acid of alpha-methylindol andsecondly isolating the dyestuff thus produced, substantially ashereinbefore described.

3. The herein-described new azo dyestuffs derived from indol sulfonicacids and diazo compounds of aromatic amins, which dyestuffs are, whendry and pulverized, from yellow to brown powders soluble in water and inammonia and dyeing wool from yellow to

